[SCSI] libsas: replace event locks with atomic bitops

The locks only served to make sure the pending event bitmask was updated
consistently.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index dc52b1f..ed04118 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -295,8 +295,7 @@
 		container_of(work, struct sas_discovery_event, work);
 	struct asd_sas_port *port = ev->port;
 
-	sas_begin_event(DISCE_DISCOVER_DOMAIN, &port->disc.disc_event_lock,
-			&port->disc.pending);
+	clear_bit(DISCE_DISCOVER_DOMAIN, &port->disc.pending);
 
 	if (port->port_dev)
 		return;
@@ -355,8 +354,7 @@
 		container_of(work, struct sas_discovery_event, work);
 	struct asd_sas_port *port = ev->port;
 
-	sas_begin_event(DISCE_REVALIDATE_DOMAIN, &port->disc.disc_event_lock,
-			&port->disc.pending);
+	clear_bit(DISCE_REVALIDATE_DOMAIN, &port->disc.pending);
 
 	SAS_DPRINTK("REVALIDATING DOMAIN on port %d, pid:%d\n", port->id,
 		    task_pid_nr(current));
@@ -379,8 +377,7 @@
 
 	BUG_ON(ev >= DISC_NUM_EVENTS);
 
-	sas_queue_event(ev, &disc->disc_event_lock, &disc->pending,
-			&disc->disc_work[ev].work, port->ha);
+	sas_queue_event(ev, &disc->pending, &disc->disc_work[ev].work, port->ha);
 
 	return 0;
 }
@@ -400,7 +397,6 @@
 		[DISCE_REVALIDATE_DOMAIN] = sas_revalidate_domain,
 	};
 
-	spin_lock_init(&disc->disc_event_lock);
 	disc->pending = 0;
 	for (i = 0; i < DISC_NUM_EVENTS; i++) {
 		INIT_WORK(&disc->disc_work[i].work, sas_event_fns[i]);